36 W. W. Watts— British Geological Photographs. 



many of the societies have thrown themselves heart and soul into it. 

 Many of them have already been mentioned in connection with the 

 districts in which their work lies, but there are several others, such 

 as the Chester Society of Natural Science, the Croydon Microscopical 

 Society, the Dover Natural History Society, the Geological and 

 Geographical Societies of Manchester, and the Geologists' Asso- 

 ciation, which have given ready help. Warwickshire has earned 

 out a Photographic Survey of its dominions, including not only 

 geological phenomena, but subjects of geographical, ethnographical, 

 and archcBological interest. It may not be yet possible to carry out 

 such a comprehensive scheme as this in many cases, but it ought 

 not to be difficult to get one or two enthusiastic photographers in 

 each county to register at least the prominent and temporary features 

 and phenomena of geological interest. Guidance and help, where 

 it was needed, would be forthcoming from local geologists and the 

 Survey, and it may be possible in the compass of a few years to 

 have the whole of the United Kingdom fairly well represented, so 

 that there would only remain the task, which will then have become 

 an easy one, to photograph new sections as they are exposed, and 

 new phenomena as they are recorded and understood. We should 

 thus become possessed of a storehouse of fact to which the rising 

 geologist can readily turn to see the state of knowledge at this 

 particular date, to check the older work, and to measure the progress 

 of physiographic change. 



Our present experience with the collection shows that one ot 

 the great dangers which exists is the want of permanence of sonie 

 of the prints. Kept away from the light as most of them are, it 

 seems that the ordinary silver prints last fairly well when properly 

 fixed and washed after toning; bromide prints, however, appear 

 to last better, and, of course, platinotypes best of all. It is really 

 worth while to sacrifice some of the depth and detail of shadow, at 

 present an unavoidable defect of platinotype printing, in order to 

 secure the greater permanence which these prints give. To those 

 who take small prints it may also be said that enlargements are 

 very satisfactory from the greater ease with which they can be 

 studied ; but it is advisable, by the use of a small stop or a very 

 good lens, to get the negatives from which enlargements are to he 

 prepared as sharp and clean as possible. Very good results are 

 obtained by carbon enlargements, but the process is troublesome 

 owing to the necessity for preparing an enlarged negative ; still, 

 such a negative is a valuable acquisition when once it has been made. 

 Every photographer knows the importance of illustrative drawings 

 taken at the same time as the photograph, or, better still, with the 

 photograph in hand when the section is revisited; such careful 

 work as this adds immensely to the value of the photographs as 

 a permanent record. 



Some attempt has been made to make the photographs more 

 accessible and useful by promoting exchange between contributors, 

 and the Committee can always be utilized as a means of inter- 

 communication ; some photographers have been kind enough to 



